1. Field of the Invention
The present invention is directed to heddle frames and more specifically to the detachable and/or pivoted connection between the lateral support and the frame stave.
2. Prior Art
In their basic design most heddle frames consist of two frame staves which are connected at their ends by means of two lateral supports. Originally, these lateral supports were firmly rivetted or welded on the frame staves and could not be removed. Recently, however, removable lateral supports have become more common and many different constructions of heddle frames with removable lateral supports are known. The most commonly used constructions of heddle frames include lateral supports which are fixed to the frame staves by means of at least one screw extending through the lateral support into each frame stave. Up to now, two different kinds of screw joints have been used for this purpose. In the most simple construction the screw passes directly through the front of the lateral support and is fastened to the frame stave parallel to the longitudinal direction thereof. In a second screw joint construction, the lateral supports are provided with protruding portions which embrace the ends of the frame staves in the longitudinal direction of the frame staves or which protrude into hollow spaces in the frame staves. The screw in this case passes parallel to the longitudinal direction of the lateral support and connects the frame stave with the protruding portions of the lateral support. Both of the above mentioned screw joints have proved successful and will remain in use in some fields of application.
However, several disadvantages have given rise to the need to find a better detachable connection between frame staves and lateral supports. In many applications, the thickness of the lateral supports corresponds to the pitch of the shedding mechanism of the loom so that the adjoining lateral supports of heddle frames glide on each other and simultaneously serve as a guide. Screw fastening arrangements wherein the screw passes through the lateral support and is screwed into the end of the frame stave are suitable for this type of construction. However, on modern weaving machines each individual heddle frame is guided on the lateral support. The lateral supports do not glide on each other but are spaced apart a distance which is determined by guides fitted onto the weaving machine. The lateral supports for this application are mainly of metal having a profiled shape along their longitudinal axis. On such lateral supports there is usually no space available for a screw to be located. In such cases the screw is introduced parallel to the lateral support. The screw is fastened in such instances at a given distance to the lateral support from the outer edge of the frame stave. In several constructions this placement is not possible since frame stave suspension elements for driving the heddle frame have to be mounted on the outer edge of the frame staves closely adjacent to the lateral support. The limited space availability therefore often resulted in improper screw connections between the lateral supports and the frame staves.
Since the arrangement of screws in the two directions discussed above do not provide a suitable design the location of the screw in a third direction orthogonal to the longitudinal axis of the frame stave and the lateral support was considered. This variation, however, had to be eliminated since the thickness of the heddle frame in this direction was not sufficient for the length of the screw to provide a strong connection. Furthermore, the screws would not be accessible when the frames would be piled on each other or would be placed into the weaving machine.